<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>交集选择器</title>
    <!-- 交集选择器，指选中页面中满足多个选择器的标签 -->
    <!-- 选择器1选择器2，如果有标签元素则标签元素写在最前面 -->
    <style>
        p.box {
            color: red;
        }
    </style>
</head>

<body>
    <p class="box">这个是p标签</p>
    <p>ppppp</p>
    <div class="box">这是div标签</div>
</body>

</html>